DEHGHAN, Nezhad A.; MAZAHERI, H. New results in $G$-best approximation in $G$-metric spaces. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 62, n. 4, p. 567–571, 2010. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/2888. Acesso em: 6 dec. 2025.